The work presented in this grant is focused on the long term goal of better understanding the roles of HSF1 and HSF2 in spermatogenesis and early embryogenesis. According to the Center for Disease Control (CDC) infertility affects approximately 6.1 million women and their partners in the United States. Defective expression of heat shock factors leads to several phenotypes including infertility in both males and females. To identify the role(s) of HSF1 and HSF2 in reproduction, these factors must be thoroughly characterized in vivo at various stages of spermatogenesis. The role of HSF2 bookmarking the hsp70i gene in mature spermatozoa must be evaluated. Finally, all gene targets bound by HSF1 and HSF2 must be identified. [unreadable] [unreadable]